Hey Guys, i'm thinking about moving from c++ to D, but I cant
live without the Kernel32 Functions, so whats the easiest way to
use them in D?
I mean for example ReadProcessMemory etc.

Look at the src\druntime\src\core\sys\windows folder in your DMD
installation. The Windows API declarations are there. Some things are
missing, but you can just declare that yourself as needed.
Most of it is in core.sys.windows.windows, but ReadProcessMemory is
declared in core.sys.windows.dbghelp.
kernel32.lib is linked by default, so you don't need to do anything else
to get it working.